Cellulosic sponge



United States Patent CELLULOSIC SPONGE George Martin James, Columbia, Tenn., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware N0 Drawing. Filed Jan. 24, 1958, Ser. No. 710,862

14 Claims. (Cl. 117-98) This invention relates to the preparation of cellulosic sponges and, more particularly, to prolonging the useful life of such sponges.

Cellulosic sponges are subject to degradation by molds and bacteria. Preservatives to resist degradation of cellulose are known but are difiicult to retain in sponges during use. Preservatives for protecting other cellulosic products such as regenerated cellulose bands, tubing and the like tend to leach from the cellulosic sponges after several immersions of the sponge in water. Water-insoluble preservatives do not lend themselves well to aqueous processing-aqueous processing being characteristic of the manufacture of cellulosic sponges.

It is an object of the present invention to provide a cellulosic sponge highly resistant to deterioration. It is a further object to increase the useful life of such a sponge. Other'objects will appear hereinafter.

The objects are accomplished by uniformly impregnatting a cellulosic sponge with 0.1-3 0%, based on the dry weight of cellulose, of a mixture'of a rosin amine and a quaternary ammonium halide, the halogen in the quaternary ammonium halide having a molecular weight between and 80, the quaternary ammonium halide comprising 15-75% of the mixture and the rosin amine comprising the remainder. Preferably, the sponge contains about 1% of the amine-halide preservative mixture and the mixture is composed of 50% rosin amine and 50% quaternary ammonium halide. 'The most useful rosin amine in the present invention is Rosin Amine D 1 and the most useful quaternary ammonium halide is Arquad 16. I

The mixture is preferably dissolved to the extent of about 0.06% in a sponge softener bath such as the bath described in US. Patent 2,698,625. The sponge, prepared in the conventional manner as described in US. Patents 2,280,022 and 2,295,823, is passed through the softener bath, the exposure being about three minutes. After excess solution is squeezed from the sponge and the spongeis dried, the quantity of mixture remaining represents about 1% of the final weight of the sponge.

The invention will be more clearly understood by referring to the examples and discussion which follow- The examples are specific embodiments of the invention, Example I setting forth the best mode contemplated for carrying out-the invention. Unless otherwise stated, all percentages in the examples as well as in the specification and claims are by weight.

EXAMPLE I One and one-half parts of a mixture containing 50% Rosin Amine D and 50% Arquad 16 was dissolved in 2 Dehydroabietyl amine manufactured by Hercules Powder parts of diethylene glycol. This solution was then poured into a conventional softener bath and agitated. The softener bath, which contained 5% diethylene glycol, 6% sorbitol, 11% urea and 0.06% of the preservative mixture of rosin amine-quaternary ammonium chloride in water, was warmed to a temperature of about F. The cellulosic sponge, prepared in the conventional manner, was soaked in thebath for three minutes. After being squeezed in rolls to remove excess solution, the cellulosic sponge was dried. It contained 1% of the preservative mixture based on the dry weight of cellulose.

The sponge was then tested in the following manner:

(1) Sponge specimens were cut in pairs, one piece to be exposed to rotting conditions, the other to be retained for comparison. For each subsequent value obtained, a minimum of six specimens were averaged.

2) Each set to be tested was leached in water either 3 times or 50 times. Each leach consisted of immersing the sponge in fresh water until it was thoroughly wet, then removing and wringing the sponge.

(3) The leached sponges wereeach painted on their two large faces with a slurry of well-composted garden soil in water until the weight of each painted sponge was six times its original weight.

(4) The soil-impregnated sponges were placed in polyethylene bags and squeezed in the bags to distribute soil uniformly throughout the sponge. The bags were sealed by use of staples to minimize water evaporation but not to provide an air-tight seal.

(5) The bags of sponges were placed in a heated cabinet maintained at 36i1 C., the edge of the sponge resting on a shelf in the cabinet, for periods of either 6, 10 or 13 days. The bags were rotated through at least once during each period.

(6) The exposed or rotted sponge and the retained or original sponge of each pair were tested for tensile strength on a standard machine and the percent retained strength was obtained from the following formula:

lbs. necessary to pull apart rotted sponge lbs. necessary to pull apart. original sponge In Table 1 the results for the sponge treated according to the present example after 3 and 5 0 leaches and exposure to 6, 10 and 13 days of rotting conditions are compared to those of three controls: control A wherein the rosin amine alone instead of the mixture was used in the softener bath; control B wherein only the quaternary ammonium chlorides were added to the softener bath; and control C wherein the softener bath without the amine or the chlorides was used. The leaching steps were omitted for control C.

Table 1 RETAINED STRENGTH OF LEACHED SPONGES AFTER EXPOSURE TO ROTTING CONDITIONS 3 EXAMPLE n Diisobutyl phenoxy ethoxy ethyl dimethyl benzyl ammonium chloride was dissolved in water to form a solution. This solution was then added to Staybelite amine with constant sti r ng until the quaternary ammonium chloride represented 60% of the mixture of chloride and rosin amine. After the addition of more water, the resulting solution was added to a sponge-softener bath having the composition disclosed in Example I. The final concentration of the quaternary ammonium chloriderosin amine mixture, the preservative mixture, in the softener bath was about 0.06%. The cellulose sponge, prepared in the conventional manner, was alternately sprayed with the bath and squeezed by the rolls ten times over a period of, four minutes. After drying, the

sponge contained 1% of the preservative mixture based on the dry weight of cellulose.

Sponge specimens were then tested in the manner described for Example I. In Table 2 the results of the tests are compared to those for three controls: control A wherein the Stay-bclite amine alone instead of the mixture was used in the softener bath; control B wherein only diisobutyl phenoxy ethoxy ethyl dimethyl benzyl ammonium chloride was added to the softener bath; and control C wherein the softener bath without the rosin amine or the quaternary ammonium chloride was used.

Table 2 EXAMPLE III A preservative mixture composed 80% of polyethanol rosin amine with four moles of ethylene oxide and of an alkyl dimethyl benzyl ammonium chloride, the alkyl radical being C H and C14H29, was stirred until uniformly blended. A small amount of water was then'added and stirred into the mixture to form a creamy paste. Next, small amounts of water were added with stirring to make a thin, pourable paste having a concentration of perser-vative mixture of about This paste was then poured slowly with agitation into the softener solution disclosed in Example I. The final concentration of the quaternary ammonium halide-rosin amine mixture, the preservative mixture, in the softener bath was approximately 0.1%. The cellulose sponge, prepared in the conventional manner, was then treated with the softener bath in the manner described for Example II. After drying, the sponge contained about 1.5% of the perservative mixture based on the dry weight of cellulose.

Sponge specimens were then tested in the manner described for Example I. In Table 3 the results of the tests are compared to those for three controls: control A wherein the polyethanol rosin amine alone instead of the mixture was used in the softener bath; control B wherein only the quaternary ammonium chloride was added to the softener bath; and control 0 wherein the softener bath without the rosin amine or the chloride was used.

' A modified rosin amine (largely tetrahydronbietryl amine) itabiizeg against air oxidation manufactured by Hercules ow er 0.

4 Table 3 RETAINED STRENGTH 0F LEACHED SPONGES AFTER EXPOSURE TO ROTTING CONDITIONS Percent Retained Strength After- 6 days 10 days 13 days 6 days 10 days 13 days Example III 93 63 32 81 49 20 Control A 75 40 8 64 28 0 62 25 Q 30 5 0 Control 0 l 25 2 0 25 2 0 Sponges Previously Sponges Previously Leeched 3 Times Leeched 50 Times 1 Control 0 was not leached.

EXAMPLE IV A preservative mixture composed 25% of Foral Amine 4 and 75% of tridecyl benzyl hydroxyethyl imidazolinium chloride was blended and made into a pourable paste having a total concentration of preservative mixture of about 25 in the manner described for Example III, This paste was then added to the softener solution disclosed in Example I with agitation so that the final concentration of the quaternary ammonium halide-rosin amine mixture, the preservative mixture, in the softener bath was approximately 0.1%. The cellulose sponge was then treated with the softener solution in the manner described for Example II. After drying, the sponge contained about 1.3% of the reservative mixt re based on the ry Wei of cellulose.

Sponge specimens were then tested in the manner described for Example I. In Table 4 the results of the tests are compared to those for three controls: control A wherein Foral Amine alone instead of the mixture was used in the softenerbath; control B wherein only tridecyl benzyl hydroxyethyl imidazolinium chloride was added to the softener bath; and control C wherein the softener bath without the rosin airline or the quaternary ammonium chloride was used.

Table 4 RETAINED STRENGTH OF LEACHED SPONGES AFTER EXPOSURE TO ROTTING CONDITIONS control C was not leached,

The resin amines useful in the present invention inclnde primary amines derived fr m stabilized res ns and stabilized rosin acids wherein the carboxyl group has been converted into a CH NH2 group, These include dehydroahietyl amine derived from dehydrogenated rosin; dihydroand tetra-hy r a i yl amines derived from hydrogenated gum or wood rosin; and h fl mentioned amines deri d from p stabilized rosin acids. Stabilized rosin amine is meant to include primary amines having a ring structure of a stabilized rosin acid such as dehydro-, dihydro-, tetrahydroor polyabieticacid or a mixture of such primary amines. It should be understood that dehydroabietyl amines and the other hydroabietyl amines refer to rosin amines wherein the aforementioned amines are the major constituents. It is notintended that min r amounts of other materials derivedfrom the dehydrogenated rosins or hydrogenated rosins be excluded when preparing the aforementioned rosin amines. In addition to the sta bilized rosin amines described above, the following rosin amines or complexes thereof may be used in the present invention: rosinamine pentachlorophenate, polyethanol rosin-amine with no morethanfour moles of ethylene Oxide, complexes of rosin amines with copper acetate or zinc dimethyl dithiocarbonate.

In preparing the rosin amines, the rosin, dehydrogenated or hydrogenated, is first reacted with ammonia to form the nitrile. This may be accomplished by passing gaseous ammonia over the molten rosin and vaporizingthe. water as fast as it is formed or by heatinga mixtur'e'of the rosin 'and'ammonia in the presence of a dehydration catalyst. The nitrile is then purified by alkali extraction or by distillation to remove unconverted acids. After purification the nitrile is hydrogenated to form the amine. Hydrogenation may be carried out in the presence of any of the well-known hydrogenation catalysts such as Raney nickel, Raney cobalt, activated nickel, cobalt, palladium, platinum, etc. Hydrogenation is usually carried out under a pressure of 200-8,000 pounds/square inch, at a temperature between 20 and 200 C. and, if desired, in the presence of ammonia.

The quaternary ammonium halides useful in the present invention are those that are water-soluble and in which the halogen has a molecular weight of 35-80. Preferred quaternary ammonium halides include lauryl dimethyl benzyl ammonium chloride, cetyl trimethyl ammonium chloride, cetyl dimethyl ethyl ammonium chloride, tridecyl benzyl hydroxyethyl imidazolinium chloride, lauryl pyridium chloride, myristamido propyl dimethyl benzyl ammonium chloride, stearyl trimethyl ammonium bromide, octadecyl dimethyl benzyl ammonium bromide, and diisobutyl phenoxy ethoxy ethyl dimethyl benzyl ammonium chloride.

The preparation of the preservative mixture for the present invention may be accomplished in several ways. The rosin amine and the quaternary ammonium halide may be first mixed together and then emulsified by slowly adding water while agitating the mixture. Alternatively, the mixture may be dissolved in a solvent such as diethylene glycol and this solution in the glycol may be added to the sponge-softener bath. As another alternative, the quaternary ammonium halide may first be dissolved in water to form a solution. To this solution, the rosin amine may be slowly added with constant stirring. After additional. dilution with water this solution of the mixture may be added to the sponge-softener bath.

As is apparent from the preceding disclosure, the preservative mixture is preferably applied to the cellulose sponge as part of the sponge-softener bath. In the manufacture of cellulose sponges an alkaline cellulose solution such as viscose is mixed with a pore-forming material together with some fibrous material. Salt crystals such as decahydrated sodium sulfate (Glaubers salt) are generally used as the pore-forming material and cotton, flax or hemp fibers have been employed as the fibrous material. This mixture is formed into a paste which is introduced into molds where coagulation and decomposition or regeneration are accomplished in a manner well known to those skilled in the art. Salts and other impurities are then washed from the shaped regenerated cellulose articles to form the regenerated cellulose sponge. As the final treatment in a series of wet treatments, the sponges are subjected to a softening bath consisting essentially of diethylene glycol or glycerol or the like dissolved in water. In the preferred form of the present invention, the preservative mixture is incorporated in the softener bath prior to treatment of the sponge.

It is immaterial how the sponges are subjected to the softener bath. Thevsoftener solution-may be' applied to the sponge by soaking, spraying or by alternately squeezing the sponges and applyingthe liquid between rolls. The degree of protection to deterioration imparted to the sponge, i.e., the amount of the preservative mixture applied to the spongebe'tween 0.1%. and 3.0%, may be regulated by the concentration of the'preservative mixture betweenabout 0.01% and about 0.25% in the softener bath; the length of time of treatment; and the temperature of the processing. After being impregnated with the softener solution, the sponge is cut to the'desired dimensions and dried. It is believed that the final drying step sets the preservative mixture in the cellulosic sponge.

It has been observed that the inclusion of the present mixture in the sponge-softener bath does not affect the clarity of the softener solution. It is believed that the water-soluble quaternary ammonium compound tends to solubilize the rosin amine and thus maintain the aforementioned clarity of the softener solution. It has also been discovered that the preservative mixture in the bath remains stable over long periods of time, being 'virtually unaffected by impurities in the bath. The most surprising discovery, however, is the resistance to leaching of the preservative mixture when incorporated in regenerated cellulose articles. This is particularly surprising when the resistance of the mixture is compared to the relatively low resistances to leaching of the individual compounds that make up the mixture. This is critical to the manufacture of regenerated cellulose sponges, which, in ordinary usage as cleaning articles, are subject to repeated contacts with water.

What is claimed is:

1. A cellulosic sponge impregnated with 0.13.0%, based on the dry weight of cellulose, of a mixture of a rosin amine and a quaternary ammonium halide, the halogen in the quaternary ammonium halide being a member of the group consisting of chlorine and bromine, the quaternary ammonium halide comprising 15-75% of said mixture and the rosin amine comprising the remainder.

2. A cellulosic sponge as in claim 1 wherein the rosin amine is dehydroabietyl amine.

3. A cellulosic sponge as in claim 1 wherein the rosin amine is polyethanol rosin amine with four moles of ethylene oxide.

4. A cellulosic sponge as in claim 1 wherein the rosin amine is dihydroabietyl amine.

5. A cellulosic sponge as in claim 1 wherein the rosin amine is tetrahydroabietyl amine.

6. A cellulosic sponge as in claim 1 wherein the qua ternary ammonium halide is hexadecyl trimethyl am monium chloride.

7. A cellulosic sponge as in claim 1 wherein the quaternary ammonium halide is diisobutyl phenoxy ethoxy ethyl dimethyl benzyl ammonium chloride.

8. A cellulosic sponge as in claim 1 wherein the quaternary ammonium halide is an alkyl dimethyl benzyl ammonium chloride.

9. A cellulosic sponge as in claim 1 wherein the quaternary ammonium halide is tridecyl benzyl hydroxy ethyl imidazolinium chloride.

10. A cellulosic sponge as in claim 1 wherein the sponge contains about 1%, based on the dry weight of cellulose, of the mixture of rosin amine and quaternary ammonium halide.

11. A cellulosic sponge as in claim 1 wherein the mixture of rosin amine and quaternary ammonium halide is composed of 50% rosin amine and 50% quaternary ammonium halide.

12. In a process for preparing regenerated cellulose sponges which comprises the steps of mixing an alkal-ine cellulose solution, a pore-forming material and a fibrous material; shaping said mixture into structures;

r g ner t ng the ellulo e nd separating alts a d oth r impurit es from said structures to form regenerated eel lulose sponges; ubjecting said reg ner ted cellulo e sponges to a soiftener solution and drying h SPQ the improvement which comprises incorporating a mixture comp sed of 15=75% quaternary ammonium halide and -8 f r in mi e t the extent of 0.014 25% n th sof n r bath the ha ogen of the quaternary ammohalide be ng a m mber of he group onsi ting of chlorine and brom n V 1. A ellulosi sp nge imp egnated with (DJ-3.9%, base on. he dry ght f eellt lo e, ot a mixture o dehyd oabie yl mine and n alkyl imethyl ammon um chloride, said alkyl trimethyl ammonium chloride prising 15s-7 5% of said mixture and l dehydroabiety] amine comprising the remainder.

14. In a process for preparing regenerated cellulose sponges which comprises the steps of mixing an alkaline ce l lo e solutio a pe et rmin ma eri' lend a fi rous mat ial; sh p g s d mixtu i to structures; reg n rsting the cellulose nd p rating salts and other purit s from said s ru tures to fo m eg nerat d eellulose p ge subje ting said regenerated c llul se s nges o a soft n so tion. nd dryi g t e sponge, the impr vement, hich comprise ine rpor ting a ture compos d 15-75% o an e ky tr methyl nium chloride nd 5-85% of tiehyrlroabietyl mine to 10 he exten of Q.0l-0- 5% in he so teae bath- .Reterenees C t d. in the tile of this pa ent UNITED STATES PATENTS ill "s".- 91: 10, 1953 

1. A CELLULOSIC SPONGE IMPREGNATED WITH 0.1-3.0%, BASED ON THE DRY WEIGHT OF CELLULOSE, OF A MIXTURE OF A ROSIN AMINE AND A QUATERNARY AMMONIUM HALIDE, THE HALOGEN IN THE QUATERNARY AMMONIUM HALIDE BEING A MEMBER OF THE GROUP CONSISTING OF CHLORINE AND BROMINE, THE QUATERNARY AMMONIUM HALIDE COMPRISING 15-75% OF SAID MIXTURE AND THE ROSIN AMINE COMPRISING THE REMAINDER. 